Bearing removal

[3Lfarms]

I have a problem I have thus far been unable to figure out and I’m wondering if one of you can give me an idea how I can remove this bearing without causing any damage to either the bearing or shaft.




I can’t tell you what it’s for, but it is an aircraft part. Problem is, I can’t get a new bearing, but I need the bearing removed to mag particle inspect the shaft. We need to be able to inspect and reuse the bearing. The lead time to get a new certified bearing is almost a year.

The space between the bearing and splined area is so small a standard bearing separator can’t fit between the bearing and splines.
I broke one bearing trying to hold it in a vice so I could press out the shaft.

The bearing is a press fit on the shaft and it took a about half a ton of pressure to get the inner race of the broken bearing off the shaft.

Is there a special tool that could help me?

 

[user.69169]

Can it come down shaft or has it gotta come off gear end? Can't tell from picture if bearing is shouldered on shaft size.

 

[JPRambo]

google bearing separater. It goes between bearing and gear and will push the bearing off shaft

 

[3Lfarms]

The shaft/gear part is one piece. The bearing comes down off the shaft. The inner race is up against a small shoulder.
I have a Proto bearing separator, but the two sides of the wedges are too thick to get between the bearing and separator. If there was more space between the bearing and that large portion of the shaft, this wouldn’t be an issue.
The other issue is I don’t want to gouge the cadmium plating on the shaft or the shaft itself.
Is there a bearing separator that is very thin that could get in there?

I have an induction heater that I could heat the bearing with, and I I am wondering if I combine that with spraying the shaft with a cold shot, that the bearing might loosen up. I don’t really think that would work though. I think the diameter of the shaft is too small to get enough separation to let the bearing fall off.

 

[flyerdan]

If it took that much force to get the other one off, I can't imagine that a bearing separator that would be thin enough to get in there would hold up to the pressure.
It kinda looks like it might be from a magneto, do you have a component overhaul manual for (whatever) it is? That might spec out the removal process.

 

[JPRambo]

Maybe Bindian will look at this thread and offer a solution. I believe she was an aircraft mechanic.

 

[user.69169]

1, make shield to protect bearing- siding flashing plenty enough & pack bearing wid grease.
2, make barrel of PVC pipe 1/4 shorter den shaft from bearing face to end shaft
3, drill hole in PVC maybe 7/16 just below end & second hole 180° from first at other end of pipe.
4, set up pipe so it don't fall over on bench heavy bench top best. Sit hardwood block next to pipe end grain up.
5, oil up plated shaftor thin coat of grease
6, slip protective plate into place
7, install inductive heater onto bearing.
8, Heat bearing wid inductive
9, Stick hose from Co2 extinguisher in top hole just below bearing and blast shaft immediately below bearing.
10, real quick, pull inductive, grab gear wid rag & gloved hand
11, real quick, pull dry ice coated shaft out of pipe and sharply strike shaft end on wood block.

Shrunk shaft + expanded bearing should move bearing down shaft. Scrape dry ice off shaft and continue rapping on block.
Grease + shield protect bearing from carbonic acid corrosion. Best idea put bearing & shaft in part washer and clean, den use proper lube to protect.

Alternate, grind thin pickle fork to go between bearing & gear and hope it works.

 

[Ortimber]

The shaft/gear part is one piece. The bearing comes down off the shaft. The inner race is up against a small shoulder.
I have a Proto bearing separator, but the two sides of the wedges are too thick to get between the bearing and separator. If there was more space between the bearing and that large portion of the shaft, this wouldn’t be an issue.
The other issue is I don’t want to gouge the cadmium plating on the shaft or the shaft itself.
Is there a bearing separator that is very thin that could get in there?

I have an induction heater that I could heat the bearing with, and I I am wondering if I combine that with spraying the shaft with a cold shot, that the bearing might loosen up. I don’t really think that would work though. I think the diameter of the shaft is too small to get enough separation to let the bearing fall off.

Wouldn't heating the bearing ruin the seals and grease inside??

 

[ruffdog]

The correct bearing splitter has knife edges and could easily get between the gear and bearing. It looks like the gap is about .040" so that is plenty of room to start.

 

[BravoXray]

It looks like about the only way to get that off without damaging either part would be to have a collet made that would be in a couple pieces with a small ridge at the bottom to catch the bottom of the bearing race,a capture sleeve would be put over it to clamp the collet in place and give a surface to press against.

Maybe this drawing will clarify what I mean.

I had a similar problem years ago on a governor shaft on an old stationary engine.
Had a machine shop make the collets, and it pressed off no problem.

 

[user.69169]

Bearing separator gotta contact & index hub before pulling er gonna do damage to outer race. NO force should be applied to uter race.

 

[Leejohn]

The correct bearing splitter has knife edges and could easily get between the gear and bearing. It looks like the gap is about .040" so that is plenty of room to start.

You are right... One with sharp tapered starting edge.

 

[ruffdog]

But....pulling on the outer race is a no-no. By the marks on the gear, it looks like a Hy-vo silent type chain rides on it. Unless there are access holes through the gear to the inner race, I don't see how you could pull the bearing without sacrificing it.

 

[the old grind]

Turn a pair/set of the thick-edged bearing grippers over and grind the flat sides flat/flush to thin the lips.

Pressing the outer race is far less likely to cause damage than any impact method of moving it out, even just enuf to get puller jaws behind it.

btw, I'll have to re-read what (removed) Goldberg wrote. It surely makes sense, but IMO any more than three steps sounds like work.

 

[denchen]

To use heat is a no - no, but to cool the whole lot, and warm the bearing may help, especially if a puller is attached and under tension at the same time.

 

[3Lfarms]

Thanks for all the replies. There is an overhaul manual, but I just says “remove bearing”. It also assumes that I have all new bearings. Normally, used bearings go in the scrap bin and are not re-used.
The engineer just expects me to remove the bearing without causing any damage to it. I told him it’s not possible to get it off that shaft without causing some level of damage.
I have a precision parts oven. How hot could I get the whole assembly before causing damage to the seals? I would think 100 degrees C should be OK. Then try and rapidly cool the shaft with dry ice.

 

[3Lfarms]

I have a full machine shop, so I think my plan today will be to make a bearing separator out of delrin so I don’t damage the shaft.
In combination with heat/cold I think that gives me the best chance of getting the bearing to move a little so that a thin collet type puller can get behind the inner race and put it off.

 

[dodge man]

I picture making something in two halves with a half circle in the middle. Image two pieces of sheet metal that would slide between the gear and bearing. Then some kind of puller gripping the sheet metal close to the gear. The problem is sheet metal probably is not strong enough but there is not much room for anything thicker.

 

[the old grind]

To be clear, I meant to sharpen the 'blunt' inner curved edges of the puller sections.

Sometimes, just tightening the cross bolts after tucking the edges between the bearing and shoulder/gear/etc will unseat it. then finish the pull. (BTDT)

(I'm a guy who works at room temp.)

 

[3Lfarms]

I have a few of these to overhaul. I tried forcing the standard bearing separator halves in there, but the gap is just too small to get the puller in there. Ended up breaking the bearing and the spines on the shaft actually cut little grooves into the backside of the puller.
Maybe I will have to sacrifice the bearing separator. Maybe even put it in the lathe and machine it down thin enough.